[gmx-users] shall we add ions in FEP?

[Albert]

Hello:

  I found that in the free energy calculation tutorial, the ligand was 
placed in "pure" solvent which doesn't have any ions..... I am just 
wondering, will it be better to add 0.15 M NaCl in the system especially 
when we would like to calculate protein/ligand binding energy through FEP?

THX
Albert